Greben is prominent geological section and viewsight, „the most beautiful hill on the Balkan” as has been named by Žujović yet in 1900. It is located at the end of Boljetin hill, along the Danube banks at the 119 m a.s.l. altitude. The gorge Gospodjin Vir as well as the archeological site Lepenski vir is visible from its summit. Greben is made of Jurassic and Lower Cretaceous sediments that overlain Paleozoic basement (Permian clastites and volcaniclastites) and that were deposited at 1-3 km depths.